Electrical synchronizing system



may 6 1924. m zfizg J. H. HUNT ELEGTRI CAL SYNCHRONI Z ING SYSTEM Filed Sept. 11, 1920 3 sheet-s -Sheet 1 5 w J m May 6, 1924. 1,492,728

J. H. HUNT ELECTRICAL SYNCHRONIZING SYSTEM Filed Sept. 11 1920 3 Sheets-Sheet 2 ma a 1924c J. H. HUNT ELECTRICAL SYNCHRONIZING SYSTEM Filed Sept. 11 1920 3 Sheets-Sheet 5 QIQQNNQQQQ Patented May 6, 1924.

JOHN H. HUNT, OF DAYTON, OHIO, ASSIGNO'B TO THE DAYTON ENGINEERING LABORA- TORIES COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

v 1,492,728 PATENT OFFICE.

ELECTRICAL SYN'CHBONIZING SYSTEM.

Application filed September 11, 1920. Serial No. 409,586.

To all whom it may concern Be it known that I, JOHN H. HUNT, a citizen of theUnited States of America, residing at Dayton, county of Montgomery, State of Ohio, have invented 'oertainnew and useful Improvements in Electrical Synchronizin Systems, of which the following is aull, clear, and exact description.

This invention relates to electrical synchronizing systems. v

It is among the objects of the present invention to provide forsthe accurate timing of the action of an electromagnet relative.

to other moving elements.

This object is attained by overcoming the electrical lag in building up magnetism in an electromagnet.

The preferred method is to store 11 electrical energy in an inductive circuit uring a portion of the cycle of operation of the moving elements, then at a redetermined time of said cycle, to sudden y release this accumulated ener in order to ener 'ze the electroma et wi th the least possi le delay, there y tending to reduce electric lag.

In the present form, this system is shown in connection with an internal-combustion engine and a machine gun, for the purpose of timing the fire of said gun in phase with' an aeroplane propeller driven by the engine. Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the present invention are clearl shown.

In the rawings; Fig. 1 is a part structural and part diagrammatic'view of the various elements of the system in their relative positions, the respective circuit connections for these elements also being shown;

Fig, 1 is a diagram of a modification of the invention. shown in Fig. 1.

Fig. 2 is a view similar to Fig. 1 of a further modified form of the invention;

Fig. 3 is a diagrammatic view showing the status of the circuit breakers shown in Fig. 1, iluring one revolution of the propeller; an v Fig. 4 is a view similar to Fig. 3 showing the status of the circuit breakers in the modified form of Fig. 2, during one revolution of the propeller.

-Referrmg to the drawings, the source of electrical energy is shown comprising a storage battery 20 adapted to be brought into circuit connections with an inductive circuit 21 by means of a mechanically operated make and break device 22. This make and break device includes a stationary contact 23 cooperating with a movable contact 24 which is adapted to be intermittently actuated by a rotatin cam 25. This cam 25 is secured to a sha 26 carrying a gear 27 which'in turn is driven by a gear 28 mounted on the crank shaft 29 of the main driving element or engine 30. A condenser 31 .is connected across the contacts 23 and 24.

From the foregoing description it may be seen that when the contacts 23 and 24 are brought into engagement current will flow from the battery 20, wire 32, switch 50, inductive circuit 21, wire 33, movable contact 24, stationary contact 23 and back to the battery via the wire 34.

Associated with the cam 25 is another set of make and break devices including a stationa contact 35 and a movable contact 36 provi ed with a condenser 42. These contacts are in circuit relation with the batter 20, the inductive circuit 21 and the win ings 37 of the electromagnet 38 and are adapted to make and break current flowingthrough the following circuit, -from the inductive winding 21, wire 33, branch wire 39, contacts 36 and 35, wire 40, electromagnet windings 37, wires 41v and 34, battery 20, wire 32, switch 50 and back to the inductive circuit 21.

As isshown in Fig. '1, the operation of the two movable contacts 24 and 36 is controlled'by a sin le cam 25. This cam is provided with 10 es 25 so arranged as to actuate these two movable contacts in predetermined sequence for purposes describedhereinafter.

The electromagnet 38 has a core 43 which is adapted to attract an armature 44 fulcrumed at the point 45 and normally held in unattracted position by means of the spring 46. This armature 44 is combined with the firing control apparatus of a machine gun 47 carried by the engine 30 in a any sultable manner. As shown, the gun 47 is in a position directlyabove the crank shaft 29 which carries a propeller 48 at its forward extremity.

As has been mentioned heretofore, the firing of the machine gun 47 is synchronized with the operation of the engine in suclL a manner that missiles discharged from said gun will pass between the blades of the propeller 48 during its rotation.

It will of course be understood that substantially any type of machine gun may be readily used in connection with this system, it being only necessary to change the shape of the movable armature 44 to meet the requirements of the various methods of trigger release used on the difierent machine guns.

When the operator desires to discharge the machine gun, and after he has completed the usual preparations, such as cocking the gun, he closes the switch 50 which will ermit current to flow from the storage attery 20 through the inductive circuit 21 whenever the contacts 23 and 24 are in circuit closing position.

As has been described heretofore, the engine actuated cam 25 is adapted to operate the movable contacts 24 and 36 for controlling the inductive and electromagnet circuits respectively. This cam is provided with lobes 25 of equal dwell and oppositely disposed. The movable contact members 24 and 36 are so positioned relative to the cam 25 that upon rotation of said cam the movable contact 24 will first be operated to open or close the inductive circuit just before the cam 25 operates the movable contact 36 to tion of propeller 48 and cam 25 is designated by arrows 48 and 26*, respectively. From this figure it may be seen that the contacts 23 and 24 close at the point 51 on the chart, the contacts 35 and 36 closing just thereafter as shown at the point 61 of the chart. These contacts will then remain closed until points 52 and 62 are arrived at, at which ime the contacts 23 and 24 will be opened Just before the contacts 35 and 36 are opened. This operation of the contacts is again repeated at the oints 51, 52 61 and 62 It may be c early understood from the foregoing description that as long as the contacts 23 and 24 are closed current will be permitted to flow from the battery through the inductive circuit 21 thereby tending to build up a supply of energy in said circuit. During this building up of the inductive circuit the contacts 35 and 36 are also closed, thereby completing circuit connections which would normally tend to permit battery current to flow through this circuit also. However, the electro-magnet circuit being of a higher resistance than the inductive circuit the major part of the current will tend to flow through said inductive circuit, not enough current flowing through the electromagnet to affect the same. As soon as the current flowing through the inmessages the electromagnet 38, causing the armature 44 to be actuated which in turn releases the trigger mechanism and fires the machine gun. point of operation that at the point of fire the propeller blade 48 is out of alignment.

with the machine gun 47. It may also be seen that when said propeller blade is in direct alignment, as shown in the dotted lines in said figure, the two sets of contacts are in the closed, or inductive circuit building up position, at which time the gun is substantially inoperable. It may readily be seen from the chart that this device is capable of firing the gun twice during one revolution of the propeller.

Fig. 1 illustrates a synchronizing system in which the battery 20, inductive circuit 21 and magnet 38 are connected in series, and the contacts 23, 24 are connected in shunt with magnet 38. This system (lifi'ers from the system shown in Fig. 1 in that wires 33 and 40rare permanently connected, whereas in Fig' 1, the connection of wires 33 and 40 is controlled by contacts 35 and 36.

When contacts 23 and 24 close magnet 38 is short circuited, and the inductive circuit 21 begins to store energy. 23 and 24 are separated, the energy in inductive circuit 21 is released and is discharged through magnet 38, to cause the same to attract armature 44 against the resistance of spring 46. This system re- ,quires careful adjustment of the spring resistance and of the air gap between armature 44 and the core of magnet 38.

By referring to the Fig. 2 of the drawings. which illustrates a modified form, it may be seen that there is provided timing elements and 101. driven by the gears 102 and 103*, respectively, which mesh with gears 102 and 103, respectively, said gears being secured to the crank shaft 129 of the engine. The timing element 100 is provided'with a cam 125, connected to gear 102,-and.having lobes 125 adapted to operate a movable contact 124 cooperating with a stationary Contact 123. A condenser 131 is connected across these contacts. The contact 123 is connected to a storage battery 120 through the wire 134, the. opposite side of said bat- :e being connected to thecontrolling switch 150 which in turn is connected with the primary winding 121 of an inductance coil through the wire 141, the opposite side of said inductance coil being connected to It will be seen in the Fig. 3 at this When contacts the movable contact 124 through the wire close a circuit from the secondary winding 172 through electromagnet coils 137 via the wire 173. These two contacts 135 and 136 have a condenser 142 connected across.

The operation of this system is similar to that of the system described in connection with Fig. 1. The direction of rotation of propeller 148, cam 125 and cam 170 is designated by arrows 148, 126, and 170, respectively. As soon as the, operator closes the circuit through the switch 150, current will flow fromthe storage battery 120 across contacts 123 and 124, wire 133, primary winding 121, wire 141 and back to the storage battery 120. This will permit the building up of energy in the primary winding 121 of the inductance coil. 7

The contacts 135 and 136, with their controlling cam 170, are so arranged relative'to the contacts 123 and 124 that as shown in the chart of Fig. 4, they will be open during a portion of the time that the contacts 123 and 124 are closed and will close previous to the opening of said contacts 123 and 124. Contacts 135 and 136 open again before contacts 123 and 124 close. That is, when said contacts 123 and 124 open or break the circuit throughthe primary winding 121 of the inductance coil, the current induced in the secondary winding 172 of said coil will flow through the electromagnet windings 137, wire 173, across contacts 136 and 135 and back to the secondary winding, thereby tending to energize the core 143 of the electromagnet 138, causing the movable armature 144 to be actuated, which in turn will release the breaker mechanism of the gun 147 and permit a shot to be fired. As is shown in the Fig.4, the propeller 148 is out of direct alignment with the machine gun 147, providing a clear path for the missile discharge from said gun. The Fig. 4 also shows that when the propeller 148 is in direct alignment with the gun 147, see dotted lines, the contacts 123 and 124 are still in closed position, at which time the system is still in the building up process. It may also be seen that by this system, the gun may be actuated twice during one revolution of the propeller. Owing to mechanical lag in the mechanical linkage of the machine gun, it may be necessary to cause the controlling contacts to separate when the propeller is in line with the gun. when the engine is going at high speed. This would apply particularly to achine gun mechanisms with a large amount of lag.

The impressing of a high voltage current on the magnet will always efiect a correctly timed operation of the gun as contrasted with a varied timing when the battery current is relied on to operate the armature. for in the latter case the flux in the magnet at the time of tri ger release will vary with the condition 0 the gun mechanism. Owing to the facts that a. high voltage current operates the magnet only when the gun is fired, that the inductive circuit consists of but a few parts and may be made compact and that danger of accidentally discharging the inductive circuit is thereby reduced to a a minimum, the operation of the gun mechanism may be accurately timed to the phase of the propeller and the gun will not be accidentally discharged by a grounding or breaking of wires running to the magnet as is the case when the ma et is normally attracting the armature and the gun is fired by reducing the current in the magnet and releasing the armature.

While the forms of mechanisms herein shown and described constitute preferred forms of embodiments of'the invention, it is tobe understood that other forms might be adopted, all coming within the scope of the claims which follow.

What I claim is as follows:

1. In a system of electrical control, the combination with a source of electrical energy; of an inductive winding adapted to be connected therewith; an electromagnet normally connected in series with the source of energy and the inductive winding; and means operable intermittently tomake and break a short circuit around the electromagnet, thereby causing the inductive winding to discharge an induced current throughout the circuit and thereby effect a quick encrgizing of the magnet.

2. In a system of electrical control, the combination with a source of electrical energy; of an inductive winding; an electromagnet normally connected in series with said winding and the source of energy; and make and break devices capable of intermittently making and breaking a short circuit around the electromagnet, thereby causing the sequential building up and discharging of the inductive winding, to quickly energize the electromagmr' in recurrent sequence.

3. In a system of electrical control, the combination with a source of electrical energy; of an inductive winding; a. circuit making and breaking device between said source of energy and the inductive winding; an electromagnet connected in series with said source and winding; and a make and break device capable of intermittently short circuiting the electromagnet for the purposes set forth.

4. In a system of electrical control for timing the firing of a firearm with the rotation of an engine propeller, the combination of an electromagnet having an armature adapted to discharge the firearm when-the' age current on the magnet to discharge the 10 armature is moved by the magnet; an 'enfirearm. 1

gine for operating the propellemen induc- In testimony whereof I hereto afiix my tive circuit; a current source; means for signature.

connecting the magnet, current source and inductive circuit in series; and engine cper- I JU'HN HUNT- eted means for intermittently making and Witn: breaking a short circuit of the magnet H. Sonnmmmem,

whereby to impress a, relatively high voltc I. A. GREENWALD. 

